USERS MANUAL ISL85033EVAL2Z AN1585 Rev 1.00 (Small Form) Wide VIN Dual Standard Buck Regulator With 3A/3A Nov 29, 2010 Output Current - Short Form Description Key Features The ISL85033EVAL2Z kit demonstrates performance of Wide Input Voltage Range from 4.5V to 28V the ISL85033 switching regulator IC. An input range of Adjustable Output Voltage with Continuous Output 4.5V to 28V and 3A output per channel (connect in Current up to 3A per channel parallel to 6A) allows the ISL85033 to meet a wide Current Mode Control variety of POL requirements. Adjustable Switching Frequency from 300kHz to The ISL85033 is offered in a 4mmx4mm 28 Ld TQFN 2MHz package with 1mm maximum height. The complete Independent Power-Good Detection 2 converter occupies 6.25cm area. Selectable In-Phase or Out-of-Phase PWMs Switching 100 Operation Independent, Sequential, Ratiometric or Absolute 90 Tracking Between Outputs Internal 2ms Soft-start Time 80 12V 1MHz OUT Overcurrent and Hiccup Mode Short Circuit 9V 1MHz OUT Protection, Thermal Overload Protection, UVLO 70 Boot Undervoltage Detection 5V 500kHz OUT Channels are Out-of-phase, Reducing Voltage Ripple 60 3.3V 500kHz OUT and Component Size 50 Quick Setup Guide 1.8V 300kHz OUT 1. Ensure correct board connection to the supply (+ 40 to VIN1 and - to GND2) and loads prior to applying 0.0 0.5 1.0 1.5 2.0 2.5 3.0 OUTPUT LOAD (A) power, then turn on the power supply. 2. Verify the output voltage is 5V for V and 3.3V FIGURE 1. EFFICIENCY vs LOAD, T = +25C, OUT1 A V = 28V for V IN OUT2. Frequency Control ISL85033 has an FS pin that controls the frequency of operation. Programmable frequency allows for optimization between efficiency and external component size. ISL85033EVAL2Z has the switching frequency set to 500kHz (FS is tied to VCC). 1.629 SYNC Control The ISL85033 has a SI pin for external synchronization. Default board configuration has R8 = 0 to GND, which defaults to the internally selected switching frequency. Removing R8 allows the synchronization to be external between 600kHz to 4MHz. Do not leave this pin floating. Output Voltage Selection ISL85033EVAL2Z board has V set to 5V and V set OUT1 OUT2 to 3.3V. The output voltage programming resistor, R (R 3 10 respectively), will depend on the value chosen for the feedback resistor, R (R respectively), and the desired 2 12 output voltage, V , see Equation 1. The value for R (R OUT 2 12 respectively) is typically between 1k and 10k. FIGURE 2. ISL85033EVAL2Z TOP LAYER COMPONENTS R = V V R 0.8 3 OUT1 FB 2 (EQ. 1) R = V V R 0.8 10 OUT2 FB 12 Please note that if V is less than 2.5V, switching OUT frequency and compensation must be changed for 300kHz operation due to minimum on-time limitation. Please refer to data sheet FN6676 for further information. AN1585 Rev 1.00 Page 1 of 3 Nov 29, 2010 EFFICIENCY (%) 0.595A A ISL85033EVAL2Z VCC R13 DNP NC1 A R14 VOUT1 DNP VOUT2 C1 C16 A C6 C11 R3 R10 68PF 68PF 42.2K 25.5K 12PF 12PF R1 R11 C4 R4 R9 C13 21 1 0 COMP1 COMP2 0 470PF 69.8K 69.8K 470PF R15 FB1 2 20 FB2 VIN1 VIN2 FB1 FB2 3 19 SS1 SS2 0 ISL85033IRTZ SS1 SS2 R2 R12 4 18 C2 C15 PGND1 PGND2 8.06K 8.06K OPEN BOOT1 5 17 BOOT2 OPEN BOOT1 BOOT2 U1 C5 C12 6 16 PHASE1 PHASE2 A A A 0.01UF 0.01UF A 7 15 PHASE1 PHASE2 GND1 GND4 EP 29 A A R16 FB1 FB2 L1 A L2 DNP VOUT1 VOUT2 1 2 1 2 VO1 VO2 VOUT1=5V VOUT2=3.3V 7UH 7UH D1 D2 C3 C14 SQL004 SQL004 B340B B340B R17 47UF 47UF COMP1 COMP2 DNP A A A A VIN1 VIN2 VIN1 VIN2 R18 C9 SS1 SS2 4.7UF DNP C7 C8 C10 10UF 10UF 10UF A GND2 GND3 SGND AAA A A IF VOUT1=5V (4.5V-5.5V) PLS POPULATE R26 ONLY IF VOUT2=5V (4.5V-5.5V) PLS POPULATE R27 ONLY OTHERWISE PLS LEAVE R26, R27 DNP R5 R7 R6 0 DNP 0 SYNCIN DRAWN BY: DATE: ENGINEER: SS1 SS2 PAUL ORFANU 06/21/2010 PAUL ORFANU R8 RELEASED BY: DATE: TITLE: 0 ISL85033 UPDATED BY: DATE: WIDE VIN DUAL S TIM KLEMANN 06/23/2010 A FIGURE 3. ISL85033EVAL2Z SCHEMATIC 1.875 FIGURE 4. ISL85033EVAL2Z TOP LAYER ETCH FIGURE 5. ISL85033EVAL2Z BOTTOM LAYER COMPONENTS AN1585 Rev 1.00 Page 2 of 3 Nov 29, 2010 2 1 COMP1 8 28 PGOOD1 VIN1 PGOOD1 9 27 VCC VIN1 FS 10 26 EN1 NC VCC 11 25 VCC SGND SYNCIN 12 24 EN2 SYNCIN 13 23 VIN2 SYNCOUT SYNCOUT 14 PGOOD2 22 VIN2 PGOOD2 1.500 COMP2 2 1 A A